Parallel and perpendicular plasma flow velocity shears are independently controlled and superimposed in magnetized plasmas using a modified plasma-synthesis method with concentrically three-segmented electron and ion emitters. The parallel flow velocity shear is observed to destabilize the electron drift-wave instability depending on the shear strength, while the perpendicular flow velocity shear superimposed on the parallel flow velocity shear is demonstrated to suppress the instability even in the presence of the parallel flow velocity shear.